Hand-brake



R. E. JACKSON.

HAND BRAKE.

APPLICATION FILED MAY 3. 1920.

Patented N 0v. 8, 1921 23 Qnvemfoz 6 05592 fJrc/man 2E U% l atto'cweq UNITED STATES PATENT OFFICE.

HAND-BRAKE.

Application filed May 3, 1920.

T 0 all 10 7mm it may concern Be it known that I, ROBERT E. JACKSON, a citizen of the United States, residin at Princeton, in the county of Mercer and tate of West Virginia, have invented certain new and useful Improvements in Hand-Brakes, of which the following is a specification.

This invention relates'to improvements in hand brakes, and more particularly to operating mechanism for hand brakes of railway cars and the like.

An important object of the invention is to provide an operating mechanism for hand brakes, whereby the force delivered is much greater than in the ordinary form of hand brakes.

In the accomplishment of my invention, I employ a multiple thread worm, rotating in fixed bearings, and a shiftable block or rack engaging the worm.

I am aware that the use of a shiftabl block and worm is old, but in the devices of this type with which I am familiar, the

loss of energy due to friction is greatly magnified and the parts of the device accordingly quickly become worn. The wear and tear on these devices is'increased by the fact that the worm screw is provided with but a single thread and must accordingly, in order to give sufficient engagement to the block, have a very low pitch in order that a suflicientnumber of threads will engage the block to prevent the thread being stripped by the pole engaged thereon. This further renders the braking action delivered very slow. lVith my device, any desired bra-king ratio and velocity of application may be obtained through the pitch or number of threads of the worm. V

The above objections I have overcome by the combination and arrangement of parts shown in the accompanying drawings, wherein like numerals designate like parts throughout, and wherein:

Figure l is a sectional view taken through apparatus embodying my invention,

Fig. 2 is a side elevation thereof, the brake rod pull block being omitted, and,

Fig. 3 is a section taken on line 33 of Fig. 1.

Referring now more particularly to the drawings, the numer l 10 indicates a casing Specification of Letters Patent.

. Patented Nov. 8, 1921.

Serial No. 378,590.

provided with apertured cars 11, which are adapted to receive, through the apertures thereof, securing means 12, by means of which the casing 10 is secured to the wall 13 of the car.

The casing 10 comprises sections 1 1 and 15, secured together by any suitable securing means 15. A multiple threaded worm 16, is mounted-in apertures 17, formed in the upper and lower ends of the casing section 14;. The upper end 18 of the worm extends without the casing and is provided with the usual operating hand wheel 19.

The casing section 15 is provided with a longitudinal slot paralleling the axes of the worm and having a substantially wide side 20, which forms the side of the slot farthest removed from the worm 16. Froin'the ends of the side 20 of the recess, the walls of the recess converge toward the worm .16, being provided at their inner ends with parallel portions 22.

A rack block 23 is slidably mounted in the recess and conforms in shape thereto, having portions extending between the parallel portions 22, provided with teeth 24, which engage the threads of the worm 16. The rear face of the block 23 or portion farthest removed from the worm 16 is spaced from the wall 20 of the recess. This rear face is provided with a longitudinal groove 26, which is centrally located and divides the rear face into spaced arms. These arms are provided with alined grooves 27, which are adapted to receive trunnions 28, secured to, or formed integrally with, rollers 29. These rollers bear against the rear wall 20 of the recess and hold the block 23 so that its teeth 24, are in firm engagement with the threads of the worm 16. It will be seen that the block cannot move toward the worm far enough to bind thereagainst.

Secured to the block 23 is a connecting member 30 which extends through suitable apertures formed in the casing and is con nected with a brake rod pull block 31.

The brake rod pull block 31 comprises an end member 32 provided with an annularly arranged depending flange 33, which is internally screw-threaded to receive a sleeve 34. The lower end of the sleeve 34 is screwthreaded to receive the flange {3.5 of a memher 36, which is slidably mounted upon the pull rod 37 of the brake. The sleeve 34 is eld against accidental displacement with I hand wheel 19 is rotated in the direction of the arrow in Fig. 1, the threads of the worm 16 passing through the rack of the block 2.3, tend to causethe teeth thereof to move back out of engagement with the threads of the worm. This thrust is taken care of by the anti-friction rollers 29. It will be observed that these rollers are of considerable size and keep the block 23 well spaced from the rear wall of the recess. They will, however, allow sufiicient shifting of the block 23 to prevent binding thereof upon the side walls 21 of the recess.

7 The construction shown in the pull block 31 is calculated to overcome any sudden stress which might otherwise be placed by the pull rod 37 on the block 23. Very often,

" in tightening brakes, particularly where the car upon which the brakes are being tightened is moving, the brake, in taking hold, grabs very suddenly and applies a sudden and forcible jerk to the pull rod thereof. It will, of course, be obvious that with the present construction, this jerk will be cushioned by the spring 39.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in theshape, size, and arrangement of parts may be resorted to without departing from the spirit said casing, said casing being provided with a longitudinal recess parallel to'the axis of said worm, said recess being tapered transi versely and having the widest portion thereof disposed at a point remote from said worm, and a block slidably mounted insaid recess and having teeth on one side engaging said worm.

3. In a device of the type described, a cas' ing, a worm rotatably mounted within said casing, said casing being provided with a longitudinal recess paralleling :the axis of said worm, said recess being transversely tapered and l'iavin'g the widest portion thereof disposed at a point remote from said worm, a block slidably mounted in said recess and having upon one side, teeth engaging said worm, and 'antifriction elements disposed between theopposite face of said block and thewall of the recess.

In testimony whereof I aflix my signature in presence of two witnesses.

ROBERT EDWARD JACKSON. Witnesses :Z-J

Josnrn H. Evans, i J. E. SULLIVAN. 

